The Relationships of Plasma Leptin, Backfat Thickness and TDN Intake across Finishing Stage of Holstein Steers

Abstract

Six 16 months old Holstein steers were offered ad libitum feed for 7 months, to determine the (1) relationships of backfat thickness (BFT) to plasma leptin, and insulin; and (2) associations of TDN intake/kg body weight (BW) to plasma leptin, BFT and insulin. Feed intake, body weight and BFT were measured on selected monthly ages from day 1 to 8, day 1 and 8, and day 8, respectively. Blood was sampled on day 8 and the plasma was analyzed for leptin, insulin, glucose, NEFA, total cholesterol and triglyceride. Body weight and BFT increased, while TDN intake per kg BW decreased from 16 to 23 months old. Plasma leptin increased and mimicked the level of insulin, resulting to significant correlation (r=0.54; p<0.002). TDN intake was negatively related to plasma leptin (r=0.49; p<0.004), insulin (r=0.41; p<0.02) and BFT at 12 to 13th rib (r=0.48; p<0.005). Backfat thickness at 12 to 13th rib was positively related to plasma leptin (r=0.45; p<0.01). Negative associations of TDN intake with plasma leptin and BFT during finishing period suggest long-term involvement of adipose tissues in the feed intake regulation of steers fed high concentrate diet.

The Relationships between Plasma Insulin-like Growth Factor (IGF)-1 and IGF-Binding Proteins (IGFBPs) to Growth Pattern, and Characteristics of Plasma IGFBPs in Steers

“…The present study found that concentration the plasma IGF-1 and IGFBP-3 concentrations were increased from 1 m to 17 m. Furthermore, the concentrations of plasma IGF-1 (r = 0.6801, n = 64, p<0.01) and IGFBP-3 (r = 0.6321, n = 64, p<0.01) were positively correlated to a gain in liveweight. This was in agreement with the finding in lambs (Roberts et al, 1990) and Holstein seers (Vega et al, 2002;2004) that plasma IGF-1 was positively correlated with an increase in liveweight. The changes in plasma IGFBP-3, with a gain in liveweight, may be an important control point for increased plasma IGF-1.…”

Association of Leptin Polymorphism with Production, Reproduction and Plasma Glucose Level in Iranian Holstein Cows

“…Association of leptin gene polymorphisms with serum leptin concentration was found during pregnancy (Liefers et al, 2003). The plasma concentration of leptin was positively correlated with plasma concentrations of insulin and glucose, and negatively correlated with plasma concentrations of growth hormone and non-esterified fatty acids (Block et al, 2001;Leury et al, 2003;Vega et al, 2004a). Plasma leptin obtained linear relationship with body weight of purebred and backcrossed Hereford (Vega et al, 2004b).…”

Plasma Leptin and Performance of Purebred and Backcrossed Hereford throughout Grazing and Feedlot Fattening

“…During summer grazing the level of plasma leptin between purebred and backcrossed was not significantly different, except during feedlot fattening where significantly higher leptin concentration in purebred compared to backcross was observed. Plasma leptin is a good indicator of body lipid contents in mouse (Frederich et al, 1995) and significantly related to body fat measures of human (Blum et al, 1997), pigs (Roberts et al, 1998, sheep (Blache et al, 2000;Ehrhardt et al, 2000) and steers (Vega, 2004). The seemingly elevated and attenuated plasma leptin of backcross and purebred respectively, maybe attributed to breed-related differences in fat metabolism during grazing, which needs further study.…”

“…Since there is low energy retention during grazing relative to feedlot (Hata and Hidari, 2001), different metabolic responses between breeds can be determined. The strong significant relationship of leptin and body fat measures across the species such as man (Blum et al, 1997), pigs (Robert et al, 1998), sheep (Blache et al, 2000;Ehrhardt et al, 2000) and steers (Vega et al, 2004) implies that the level of leptin is an indicator of body fat condition.…”